python_environments.py

# -*- coding: utf-8 -*-
"""An abstraction over virtualenv and Conda environments."""

from __future__ import (
    absolute_import, division, print_function, unicode_literals)

import json
import logging
import os
import shutil
import six
from builtins import object, open

from django.conf import settings

from readthedocs.doc_builder.config import ConfigWrapper
from readthedocs.doc_builder.constants import DOCKER_IMAGE
from readthedocs.doc_builder.loader import get_builder_class
from readthedocs.projects.constants import LOG_TEMPLATE
from readthedocs.projects.models import Feature

log = logging.getLogger(__name__)


class PythonEnvironment(object):

    """An isolated environment into which Python packages can be installed."""

    def __init__(self, version, build_env, config=None):
        self.version = version
        self.project = version.project
        self.build_env = build_env
        if config:
            self.config = config
        else:
            self.config = ConfigWrapper(version=version, yaml_config={})
        # Compute here, since it's used a lot
        self.checkout_path = self.project.checkout_path(self.version.slug)

    def _log(self, msg):
        log.info(LOG_TEMPLATE
                 .format(project=self.project.slug,
                         version=self.version.slug,
                         msg=msg))

    def delete_existing_build_dir(self):
        # Handle deleting old build dir
        build_dir = os.path.join(
            self.venv_path(),
            'build')
        if os.path.exists(build_dir):
            self._log('Removing existing build directory')
            shutil.rmtree(build_dir)

    def delete_existing_venv_dir(self):
        venv_dir = self.venv_path()
        # Handle deleting old venv dir
        if os.path.exists(venv_dir):
            self._log('Removing existing venv directory')
            shutil.rmtree(venv_dir)

    def install_package(self):
        if self.config.install_project:
            if self.config.pip_install or getattr(settings, 'USE_PIP_INSTALL', False):
                extra_req_param = ''
                if self.config.extra_requirements:
                    extra_req_param = '[{0}]'.format(
                        ','.join(self.config.extra_requirements))
                self.build_env.run(
                    'python',
                    self.venv_bin(filename='pip'),
                    'install',
                    '--ignore-installed',
                    '--cache-dir',
                    self.project.pip_cache_path,
                    '.{0}'.format(extra_req_param),
                    cwd=self.checkout_path,
                    bin_path=self.venv_bin()
                )
            else:
                self.build_env.run(
                    'python',
                    'setup.py',
                    'install',
                    '--force',
                    cwd=self.checkout_path,
                    bin_path=self.venv_bin()
                )

    def venv_bin(self, filename=None):
        """
        Return path to the virtualenv bin path, or a specific binary.

        :param filename: If specified, add this filename to the path return
        :returns: Path to virtualenv bin or filename in virtualenv bin
        """
        parts = [self.venv_path(), 'bin']
        if filename is not None:
            parts.append(filename)
        return os.path.join(*parts)

    def environment_json_path(self):
        """Return the path to the ``readthedocs-environment.json`` file."""
        return os.path.join(
            self.venv_path(),
            'readthedocs-environment.json',
        )

    @property
    def is_obsolete(self):
        """
        Determine if the Python version of the venv obsolete.

        It checks the the data stored at ``readthedocs-environment.json`` and
        compares it against the Python version in the project version to be
        built and the Docker image used to create the venv against the one in
        the project version config.

        :returns: ``True`` when it's obsolete and ``False`` otherwise

        :rtype: bool
        """
        # Always returns False if we don't have information about what Python
        # version/Docker image was used to create the venv as backward
        # compatibility.
        if not os.path.exists(self.environment_json_path()):
            return False

        try:
            with open(self.environment_json_path(), 'r') as fpath:
                environment_conf = json.load(fpath)
            env_python_version = environment_conf['python']['version']
            env_build_image = environment_conf['build']['image']
            env_build_hash = environment_conf['build']['hash']
        except (IOError, TypeError, KeyError, ValueError):
            log.error('Unable to read/parse readthedocs-environment.json file')
            return False

        build_image = self.config.build_image or DOCKER_IMAGE
        # If the user define the Python version just as a major version
        # (e.g. ``2`` or ``3``) we won't know exactly which exact version was
        # used to create the venv but we can still compare it against the new
        # one coming from the project version config.
        return any([
            env_python_version != self.config.python_full_version,
            env_build_image != build_image,
            env_build_hash != self.build_env.image_hash,
        ])

    def save_environment_json(self):
        """Save on disk Python and build image versions used to create the venv."""
        build_image = self.config.build_image or DOCKER_IMAGE
        data = {
            'python': {
                'version': self.config.python_full_version,
            },
            'build': {
                'image': build_image,
                'hash': self.build_env.image_hash,
            },
        }

        with open(self.environment_json_path(), 'w') as fpath:
            # Compatibility for Py2 and Py3. ``io.TextIOWrapper`` expects
            # unicode but ``json.dumps`` returns str in Py2.
            fpath.write(six.text_type(json.dumps(data)))


class Virtualenv(PythonEnvironment):

    """
    A virtualenv_ environment.

    .. _virtualenv: https://virtualenv.pypa.io/
    """

    def venv_path(self):
        return os.path.join(self.project.doc_path, 'envs', self.version.slug)

    def setup_base(self):
        site_packages = '--no-site-packages'
        if self.config.use_system_site_packages:
            site_packages = '--system-site-packages'
        env_path = self.venv_path()
        self.build_env.run(
            self.config.python_interpreter,
            '-mvirtualenv',
            site_packages,
            '--no-download',
            env_path,
            bin_path=None,  # Don't use virtualenv bin that doesn't exist yet
        )

    def install_core_requirements(self):
        """Install basic Read the Docs requirements into the virtualenv."""
        requirements = [
            'Pygments==2.2.0',
            # Assume semver for setuptools version, support up to next backwards
            # incompatible release
            self.project.get_feature_value(
                Feature.USE_SETUPTOOLS_LATEST,
                positive='setuptools<40',
                negative='setuptools==37.0.0',
            ),
            'docutils==0.13.1',
            'mock==1.0.1',
            'pillow==2.6.1',
            'alabaster>=0.7,<0.8,!=0.7.5',
            'commonmark==0.5.4',
            'recommonmark==0.4.0',
        ]

        if self.project.documentation_type == 'mkdocs':
            requirements.append('mkdocs==0.15.0')
        else:
            # We will assume semver here and only automate up to the next
            # backward incompatible release: 2.x
            requirements.extend([
                self.project.get_feature_value(
                    Feature.USE_SPHINX_LATEST,
                    positive='sphinx<2',
                    negative='sphinx==1.6.5',
                ),
                'sphinx-rtd-theme<0.3',
                'readthedocs-sphinx-ext<0.6'
            ])

        cmd = [
            'python',
            self.venv_bin(filename='pip'),
            'install',
            '--use-wheel',
            '--upgrade',
            '--cache-dir',
            self.project.pip_cache_path,
        ]
        if self.config.use_system_site_packages:
            # Other code expects sphinx-build to be installed inside the
            # virtualenv.  Using the -I option makes sure it gets installed
            # even if it is already installed system-wide (and
            # --system-site-packages is used)
            cmd.append('-I')
        cmd.extend(requirements)
        self.build_env.run(
            *cmd,
            bin_path=self.venv_bin()
        )

    def install_user_requirements(self):
        requirements_file_path = self.config.requirements_file
        if not requirements_file_path:
            builder_class = get_builder_class(self.project.documentation_type)
            docs_dir = (builder_class(build_env=self.build_env, python_env=self)
                        .docs_dir())
            for path in [docs_dir, '']:
                for req_file in ['pip_requirements.txt', 'requirements.txt']:
                    test_path = os.path.join(self.checkout_path, path, req_file)
                    if os.path.exists(test_path):
                        requirements_file_path = test_path
                        break

        if requirements_file_path:
            args = [
                'python',
                self.venv_bin(filename='pip'),
                'install',
            ]
            if self.project.has_feature(Feature.PIP_ALWAYS_UPGRADE):
                args += ['--upgrade']
            args += [
                '--exists-action=w',
                '--cache-dir',
                self.project.pip_cache_path,
                '-r{0}'.format(requirements_file_path),
            ]
            self.build_env.run(
                *args,
                cwd=self.checkout_path,
                bin_path=self.venv_bin()
            )


class Conda(PythonEnvironment):

    """
    A Conda_ environment.

    .. _Conda: https://conda.io/docs/
    """

    def venv_path(self):
        return os.path.join(self.project.doc_path, 'conda', self.version.slug)

    def setup_base(self):
        conda_env_path = os.path.join(self.project.doc_path, 'conda')
        version_path = os.path.join(conda_env_path, self.version.slug)

        if os.path.exists(version_path):
            # Re-create conda directory each time to keep fresh state
            self._log('Removing existing conda directory')
            shutil.rmtree(version_path)
        self.build_env.run(
            'conda',
            'env',
            'create',
            '--name',
            self.version.slug,
            '--file',
            self.config.conda_file,
            bin_path=None,  # Don't use conda bin that doesn't exist yet
        )

    def install_core_requirements(self):
        """Install basic Read the Docs requirements into the Conda env."""
        # Use conda for requirements it packages
        requirements = [
            'mock',
            'pillow',
        ]

        # Install pip-only things.
        pip_requirements = [
            'recommonmark',
        ]

        if self.project.documentation_type == 'mkdocs':
            pip_requirements.append('mkdocs')
        else:
            pip_requirements.append('readthedocs-sphinx-ext')
            requirements.extend(['sphinx', 'sphinx_rtd_theme'])

        cmd = [
            'conda',
            'install',
            '--yes',
            '--name',
            self.version.slug,
        ]
        cmd.extend(requirements)
        self.build_env.run(
            *cmd
        )

        pip_cmd = [
            'python',
            self.venv_bin(filename='pip'),
            'install',
            '-U',
            '--cache-dir',
            self.project.pip_cache_path,
        ]
        pip_cmd.extend(pip_requirements)
        self.build_env.run(
            *pip_cmd,
            bin_path=self.venv_bin()
        )

    def install_user_requirements(self):
        # as the conda environment was created by using the ``environment.yml``
        # defined by the user, there is nothing to update at this point
        pass